1. Field of the Invention
This invention relates to building construction and, more particularly, to the construction of buildings from prefabricated wall components in which such components are manufactured in a factory and then assembled on the site. Still more specifically, this invention relates to trim for the siding for such buildings.
2. Prior Art
Aluminum siding is generally designed for application to existing buildings. Accordingly, various problems are encountered when it is desired to prefabricate a wall component with aluminum siding thereon in a factory for later assembly at the job site into a completed building. For example, in applying aluminum siding to an existing building, the conventional procedure is to provide a starter strip at the bottom of the wall extending horizontally and then to mount the first corner post. Generally, the horizontal siding panels are then applied with their ends being slid into vertical grooves in the previously mounted corner posts. The corner posts serve, among other things, to help insure level and plumb mounting of the horizontal siding panels as well as preventing rain from penetrating behind the aluminum siding. One disadvantage of this system has been the fact that it is very easy to nick or dent the corner post during subsequent application of the several siding panels. In order to overcome this problem, two-piece corner posts have been provided in which a base member is secured to the building, the siding is then applied, and a finishing cap is snapped into place in engagement with the base member after application of the horizontal siding panels. However, in both instances either the corner post or the base must be mounted before the horizontal siding panels are mounted. Accordingly, the conventional trim system for aluminum sided buildings is not adaptable to use where prefabricated wall components are assembled in the factory with aluminum siding thereon. The difficulty resides in the fact that these wall components are constructed to meet at a corner and also on long walls to meet intermediate of corners with the joint between adjacent panels being so designed and constructed as to allow for variation in the foundation size. It is practically impossible to pour a concrete foundation or erect a concrete block foundation that is absolutely perfect in size. The finished foundation may vary from a fraction of an inch to as much as two or three inches plus or minus, usually plus, the intended size. That is, to say, that the foundation tends to be somewhat larger than specified. To accommodate this variation, the factory wall components are constructed such that their vertical edges, whether meeting at a corner or intermediate the corners, form a joint that may be opened up to fit the foundation. This necessitates that the siding applied in the factory also be dimensioned to accommodate variation. To this end, factory constructed preassembled wall components are finished by mounting a J-shaped channel member vertically adjacent to but spaced from the extreme edge of the wall component and nailing the same to the underlying sheathing. Such a vertically mounted J-shaped channel member is provided at both ends of the horizontal aluminum siding panels with the edges inserted within the arms of the J. When, subsequently, these walls are erected, there may or may not be filler blocks provided between adjacent vertical edges of the adjacent panels, depending upon how well the panels fit the foundation. The filler blocks are cut to the requisite size on the site and the panels secured in place. This leaves a vertical gap in the siding at the corners and on the longer walls of the building at a location intermediate the corners. For example, the conventional length for such prefabricated wall components is about twenty feet. If one of the exterior walls, as is frequently the case, exceeds this dimension, then a second wall component must be erected in the same plane which will result in a vertical gap between the J-channels of the siding. Whether at the corner or intermediate the corners, it is not possible to predict the width of this gap. Accordingly, building constructors who adopt the factory built prefabricated wall components are required to rip cut wooden strips on the site which fit the corners properly or the distance between the J-channels. These must then be painted and, at a subsequent time, the builder must return to apply a second coat in order to maintain adequate esthetic appearance. There are a number of drawbacks to this system not the least of which is the fact that the corner post is of a different material as is the "zipper" at any joint intermediate the corners of the building. Moreover, the corner posts and zippers must be cut on site, painted and repainted, adding to the cost of the building. Existing aluminum corner posts, even those with a base and snap-on cap are not suitable for use with such preassembled wall components in which the siding is applied in the factory. Further, there is no available zipper provided by aluminum siding manufacturers.